ProgressDialog在 AsyncTaskTask 中的单独使用

最新推荐文章于 2025-06-11 14:02:42 发布

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本文详细介绍AsyncTask类在Android开发中的应用实例，包括自定义AsyncTask子类实现后台任务的加载及UI更新流程，通过具体代码展示如何正确地使用onPreExecute、doInBackground与onPostExecute方法。

public class AsyncClass extends AsyncTask<Void, String, Void> {
private Context context;
ProgressDialog dialog;

public AsyncClass(Context cxt) {
context = cxt;
dialog = new ProgressDialog(context);
}

@Override
protected void onPreExecute() {
dialog.setTitle("Please wait");
dialog.show();
}

@Override
protected Void doInBackground(Void... unused) {
SystemClock.sleep(2000);
return (null);
}

@Override
protected void onPostExecute(Void unused) {
dialog.dismiss();
}
}

2.使用

private class PrepareAdapter1 extends AsyncTask<Void,Void,ContactsListCursorAdapter > {
ProgressDialog dialog;
@Override
protected void onPreExecute() {
dialog = new ProgressDialog(viewContacts.this);
dialog.setMessage(getString(R.string.please_wait_while_loading));
dialog.setIndeterminate(true);
dialog.setCancelable(false);
dialog.show();
}
/* (non-Javadoc)
* @see android.os.AsyncTask#doInBackground(Params[])
*/
@Override
protected ContactsListCursorAdapter doInBackground(Void... params) {
cur1 = objItem.getContacts();
startManagingCursor(cur1);

adapter1 = new ContactsListCursorAdapter (viewContacts.this,
R.layout.contact_for_listitem, cur1, new String[] {}, new int[] {});

return adapter1;
}

protected void onPostExecute(ContactsListCursorAdapter result) {
list.setAdapter(result);
dialog.dismiss();
}
}